Monty C. Johnson

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Antimicrobial peptides, bacteriocins, produced by lactic acid bacteria were adsorbed on the cells of producing strains and other gram-positive bacteria. pH was a crucial factor in determining the degree of adsorption of these peptides onto cell surfaces. In general, between 93 and 100% of the bacteriocin molecules were adsorbed at pHs near 6.0, and the(More)
The influence of growth parameters on the production of pediocin AcH by Pediococcus acidilactici H was studied. This strain produced large quantities of pediocin AcH in TGE broth (Trypticase [1%], glucose [1%], yeast extract [1%], Tween 80 [0.2%], Mn [0.033 mM], Mg [0.02 mM] [pH 6.5]) within 16 to 18 h at 30 to 37 degrees C (final pH, 3.6 to 3.7). Pediocin(More)
An antimicrobial peptide designated pediocin AcH was isolated from Pediococcus acidilactici strain H. The pediocin AcH was purified by ion exchange chromatography. The molecular weight of pediocin AcH was determined by SDS-PAGE to be about 2700 daltons. Pediocin AcH was sensitive to proteolytic enzymes resistant to heat and organic solvents, and active over(More)
Vasoactive intestinal peptide (VIP), a neuropeptide present in primary and secondary lymphoid organs has been previously reported to inhibit IL-2 and IL-4 production as well as the proliferation of mitogen- or antigen-stimulated T-cells. Binding studies suggested that the immunoregulatory effects of VIP are mediated through specific VIP-binding sites(More)
Vasoactive intestinal peptide (VIP), a neuropeptide present in the lymphoid microenvironment, modulates cytokine expression and affects T cell proliferation. Recent molecular studies identified two VIP receptors. VIP-R1 and VIP-R2, primarily in nonlymphoid cells. In this study, we investigate the expression of VIP-R1 and VIP-R2 mRNA in unstimulated and(More)
An SDS-PAGE technique is described that allows identification of the antimicrobial activity of a peptide secreted by a strain ofPediococcus acidilactici. This peptide has an antimicrobial property against several baeteria associated with food. This technique enables detection of the specific peptide (or protein) band(s) associated with the inhibitory effect(More)
N-terminal analysis of purified pediocin AcH produced a partial sequence of 23 amino acids. This sequence matched perfectly with a segment of 23 amino acids in a 62 amino acid molecule generated from the 186 nucleotide sequence open reading frame in a Hind III fragment in pSMB74 encoding pap-gene (pediocin AcH production). It is suggested that the molecule(More)
Pediococcus acidilactici strains E, F and H isolated from fermented sausages produced bacteriocins which were protein in nature and inhibitory to a variety of spoilage and pathogenic microorganisms often encountered in foods. These strains harbored two to three plasmids ranging in size from 7.4 to 40.2 megadaltons. Curing experiments and plasmid profile(More)
Pediocin AcH, a bacteriocin of Pediococcus acidilactici H, inhibits the growth of several food spoilage and pathogenic bacteria. The antigenic property of partially purified pediocin AcH was tested by immunizing mice and a rabbit. Pediocin AcH was not immunogenic in these animals as determined by immunoblotting even after conjugation to bovine serum(More)
Recent studies by DNA-DNA hybridization revealed that strains now designated as L. acidophilus, can be divided into several groups and only one group should be classified as L. acidophilus. We studied several phenotypic characteristics in representative strains from the six DNA-homology groups of L. acidophilus. No group specific pattern was observed among(More)